Last year, Philip Franks played Dr Watson to Peter Egan’s Sherlock Holmes in a technologically ambitious touring production of The Hound of the Baskervilles, and the veteran board treaders are playing the double act in The Secret of Sherlock Holmes, which opens at Richmond Theatre on Monday.

The play, written by Jeremy Paul, was first staged in the West End in 1988 with Jeremy Brett and Edward Hardwicke reprising their roles as Holmes and Watson from the popular TV series The Adventures of Sherlock Holmes, and Franks says that, compared to the The Hound of the Baskervilles, this production is a very different beast.

“It is not a gung-ho adventure like Baskervilles was – there is one big special effect but the show doesn’t rely on effects or big screens,” he says.

“This is a psychological drama and it has got all the thrills and spills you’d expect from a Sherlock Holmes story but it is much more about Holmes and Watson’s relationship.

“It was also written with Jeremy Brett and Edward Hardwicke in mind, so you are getting an intelligent Watson, rather than a bumbling one, and a Holmes who is unstable.”

The first half of the play is a whistlestop tour of Watson and Holmes’s partnership, from their first meeting through to Conan Doyle’s attempt to kill Holmes off at Reichenbach Falls, with the second half being a mix of original material and elements taken from the final Holmes story, The Adventure of the Empty House.

Now, 123 years after the first Holmes story appeared, Conan Doyle’s creation continues to enthrall readers, theatre audiences and filmgoers alike.

In the summer, Guy Ritchie disproved the theory that he can’t even direct traffic by helming a phenomenally successful Sherlock Holmes film, with a sequel already in the pipeline.

“Everyone loves a mystery, from an episode of Poirot to doing a crossword,” says Franks.

“There is a satisfying cleverness to the books and Conan Doyle hit upon one of the great literary double-acts of all time.

“They have such a hold on the imagination that we think of them as real people – once in a blue moon literary characters come along that have an autonymous life outside the fiction in which they appear.”

Is he worried how about following in the footsteps of Jude Law, who plays Watson in the Ritchie picture?

“I’m obviously much better looking,” he replies with a laugh.

The Secret of Sherlock Holmes, Richmond Theatre, March 1-6, for more information and to book tickets, visit ambassadortickets.com